1. Field of the Invention
The field of this invention relates to fiberoptic fibers and more particularly to the bundling together of a plurality of fiberoptic fibers which are used to transmit light pulses from an appropriate light source.
2. Description of the Related Art
Typical fiberoptic fibers are constructed of pure silica or doped silica glass and include a center core about which is located a cladding. Both the core and the cladding are constructed of silica glass. Typically, a fiberoptic fiber is one hundred and twenty five microns in diameter. Some cores could be as small as four to ten microns (single mode) in diameter while other cores may be fifty microns (multimode) in diameter or greater. This means that the cladding can range from a thickness of less than thirty microns to greater than sixty microns. The light that is being transmitted by the core is confined to the core by the cladding. Any attempt by the light to exit the side of the core is reflected by total internal reflection. Typically core cladding configuration is constructed according to the particular usage. For example, a core could be constructed to transmit light pulses in the range of six hundred and thirty nanometers (nm), eight hundred and fifty nanometers, nine hundred and ten nanometers, thirteen hundred nanometers or fifteen hundred and fifty nanometers. It is to be understood that the foregoing nanometer range is typical but actually the fiber could be constructed to transmit any nanometer value of light.
Generally, a plurality of the fiberoptic fibers are bundled together in a tightly packed environment. This bundle of fiberoptic fibers has a light entry end with this light entry end to be connected to an appropriate light source. This appropriate light source can transmit a different signal within each fiber or it could transmit the same signal within each fiber. The number of fibers within a bundle can be two in number or could actually be thousands in number. The fibers are mounted in a sleeve which comprises the tightly packed environment. A typical prior art sleeve has a circular through passage. It has been found that placing the fibers within a circular through passage, and even though such are tightly restrained, some of the fibers will actually assume slightly non-parallel positions relative to other fibers. The efficiency of transmission of the light is significantly improved if all of the fibers in the bundle are located precisely parallel to each other. The greater the parallel relationship of the fibers at the entry end of the bundle, the greater the efficiency of transmission.
A typical sleeve that is used to tightly restrain the bundle of fiberoptic fibers is generally in the range of ten to twenty millimeters in length. Generally, the longer the sleeve, the greater the chance that the fibers that are restrained by the sleeve are located more precisely parallel to each other. However, because the sleeve contains a circular through passage, it has been found to be difficult to achieve the high degree of parallel relationship between the fibers that is required. Bundled fibers are used to transmit light pulses.
During the manufacturing of a bundle of fibers, it may be necessary to measure the angular deviation between the fibers to make sure that the fibers are located within a certain tolerance factor. The bundle of fibers prior to being placed within the aligning sleeve are impregnated with an epoxy resin. The grouping of the fibers is then forced into the aligning sleeve and the resin permitted to harden. The outer end of the fibers are then cut forming an entry end for the transmission of the signals which is in alignment with the outer end of the aligning sleeve. When testing for angular deviation to determine if there is any fiber that is not within the selected tolerance for deviation, which occurs after curing of the epoxy resin, any fiber that is not within the selected tolerance level will cause the bundle of fibers to be rejected and not be usable. In the past, this rejection level during manufacture can exceed fifty percent. This is an exceedingly high degree of rejection and greatly magnifies manufacturing cost. It would be desirable to design an aligning sleeve in a manner to substantially eliminate the rejection of the bundled fibers so that all of the fibers within the aligning sleeve are located precisely parallel to each other. This will mean that the projected light emanated from each fiber will be accurately defined.
The first basic embodiment of the present invention comprises constructing an aligning sleeve for a bundle of fiberoptic cylindrical fibers which has an elongated body formed of a rigid material with the body having a fore end and an aft end. A through passage is formed within the body extending from the fore end to the aft end. The through passage is hexagonally shaped in transverse cross-section forming six in number of evenly spaced longitudinal corners with a single fiberoptic fiber to nest in a corner defining a series of corner fibers. A corner is defined as a longitudinal joint connecting two flat surfaces of the hexagonal shaped through passage. The corner can be sharply formed or rounded. All remaining fibers of the bundle precisely align with these corner fibers resulting in all the fibers in the bundle being located parallel to each other as such are tightly packed within the through passage of the sleeve.
A further embodiment of the present invention is where the basic embodiment is modified by the aligning sleeve being cylindrical.
A further embodiment of the present invention is where the basic embodiment is modified by the aligning sleeve being constructed of glass or other suitable materials.
A further embodiment of the present invention is where the basic embodiment is modified by the through passage being centrally located within the elongated body of the aligning sleeve.
A further embodiment of the present invention is where the basic embodiment is modified by the including of an enlarged tapered opening within the aft end of the sleeve to assist in the guiding and insertion of the fibers within the through passage of the elongated body of the aligning sleeve.
A further embodiment of the present invention is where the basic embodiment is modified by the fiberoptic cylindrical fibers being all of the same diameter.
A second basic embodiment of the present invention is directed to the combination of the fiberoptic fibers of the bundle in conjunction with the aligning sleeve with the number of the fibers within the fiberoptic bundle being within the group of 7, 19, 37, 61, 91, 127, 169, 217, 271, 331 . . . The aligning sleeve has an elongated body formed of a rigid material with the body having a fore end and an aft end. A through passage is formed within the body extending from the fore end to the aft end with this through passage being hexagonally shaped in transverse cross-section forming six in number of evenly spaced longitudinal corners with a single fiberoptic cable to nest in a corner forming a plurality of parallel corner fibers. All remaining fibers of the bundle of fibers precisely align with the corner fibers so that all the fibers in the bundle are located parallel to each other. Utilizing of the aligning sleeve of the present invention essentially eliminates the rejection in the manufacturing of a bundle of fibers due to excessive angular deviation and subsequently also eliminated the testing of the angular deviation of the fibers thereby eliminating a manufacturing step because it is assured that all fibers will be located essentially precisely parallel to each other within the bundle.
A further embodiment of the present invention is where the second basic embodiment is modified by the cylindrical fibers of the bundled fibers all being of the same diameter.
A further embodiment of the present invention is where the second basic embodiment is modified by the aligning sleeve being cylindrical in shape.
A further embodiment of the present invention is where the second basic embodiment is where the through passage formed within the aligning sleeve is centrally located.
A further embodiment of the present invention is where the second basic embodiment is modified by the aft end of the sleeve including an enlarged tapered opening which facilitates guiding insertion of the fiberoptic fibers within the through passage.
A further embodiment of the present invention is where the second basic embodiment is modified by there being formed within the group of fibers contained within the sleeve a centrally located fiber which can be utilized as a convenient point of reference when moving a light source from one fiber to another fiber. The centrally located fiber will be basically in alignment with the longitudinal center axis of the through passage.